Screening for treatable left ventricular abnormalities in diabetic patients

Electrocardiographic Left Ventricular Hypertrophy Among Gambian Diabetes Mellitus Patients

BACKGROUND

The global prevalence of diabetes and its complications is increasing worldwide. Its role in coronary heart disease has been linked with the presence of left ventricular hypertrophy (LVH). The present study aims to determine the prevalence of electrocardiographic left ventricular hypertrophy (ECG-LVH) in adult diabetic subjects, its epidemiological and clinical correlates.

METHODS

A descriptive cross-sectional study involving 534 patients was conducted at the Edward Francis Small Teaching Hospital (formerly Royal Victoria Teaching Hospital), The Gambia. Four hundred and forty patients were included using a standard questionnaire. Anthropometry, laboratory investigations and electrocardiogram were carried out. We used the Lewis, Cornell, and Sokolow-Lyon Voltage criteria to define ECG-LVH. Minitab™ statistical software version 13.20 was used for analysis.

RESULTS

146 (35.2%) patients had ECG-LVH using all 3 criteria and this prevalence was higher among women being 116 (79.5%). A generally high prevalence of overweight (155/37.4%) and obesity (119/28.6%) was observed among study participants, and both clinic-day systolic and diastolic blood pressure (BP) were significantly higher in those with ECG-LVH. Poor diabetes control was observed in both groups.

CONCLUSION

There was a high prevalence of ECG-LVH and it is especially so with combining multiple criteria, hence the need for screening. Clinic-day hypertension was associated with ECG-LVH hence the need for diagnosing and aggressive treatment of hypertension in patients with diabetes mellitus.

NT-proBNP in normoalbuminuric patients with Type 2 diabetes mellitus

OBJECTIVE

To examine levels of NT-proBNP and its relation to hypertension, as well as diastolic function in normoalbuminuric patients with Type 2 diabetes.

RESEARCH DESIGN AND METHODS

The study comprised 60 Type 2 diabetic patients without albuminuria. Thirty patients were normotensive and 30 had hypertension. Exclusion criteria were cardiac symptoms and an ejection fraction < 55%. Thirty age- and sex-matched normal subjects served as controls. Diastolic dysfunction was assessed with echocardiography, by means of mitral inflow and colour M-Mode flow propagation recordings.

RESULTS

Overall NT-proBNP was significantly elevated in the Type 2 diabetes group, compared with the controls [54.5 pg/ml (5-162) vs. 32.7 pg/ml (5-74.3) P = 0.02]. NT-proBNP was significantly higher among hypertensive patients compared with both normotensive patients and controls but no difference was found between the normotensive patients and the controls [58.0 pg/ml (8.5-162), P < 0.05 vs. 50.8 pg/ml (5-131) P = 0.4]. Patients with concentric and eccentric hypertrophy had significantly higher NT-proBNP levels compared with the control group [81.0 pg/ml (5-147), P < 0.001 and 66.8 pg/ml (42-128), P < 0.001], whereas patients with left ventricular remodelling (enlarged relative wall diameter but normal left ventricular mass) were comparable with the control group [42.3 pg/ml (8.3-142) P = 0.55]. Patients with left atrial enlargement also had incremental NT-proBNP values. NT-proBNP was only moderately correlated to age (r = 0.33, P < 0.05) and left ventricular diastolic diameter (r = 0.41, P < 0.05), but unrelated to diastolic function.

CONCLUSIONS

NT-proBNP is significantly increased in hypertensive, normoalbuminuric patients with Type 2 diabetes. These findings were related to left ventricular hypertrophy and increased left atrial and ventricular diameters.

Screening for heart disease in diabetic subjects

BACKGROUND

The prevalence of left ventricular hypertrophy (LVH), coronary artery disease, and subclinical cardiomyopathy in diabetic patients without known cardiac disease is unclear. We sought the frequency of these findings to determine whether plasma brain natriuretic peptide (BNP) could be used as an alternative screening tool to identify subclinical LV dysfunction.

METHODS

Asymptomatic patients with diabetes mellitus without known cardiac disease (n = 101) underwent clinical evaluation, measurement of BNP, exercise stress testing, and detailed echocardiographic assessment. After exclusion of overt dysfunction or ischemia, subclinical myocardial function was sought on the basis of myocardial systolic (Sm) and diastolic velocity (Em). Association was sought between subclinical dysfunction and clinical, biochemical, exercise, and echocardiographic variables. RESULTS; Of 101 patients, 22 had LVH and 16 had ischemia evidenced by exercise-induced wall motion abnormalities. Only 4 patients had abnormal BNP levels; BNP was significantly increased in patients with LVH. After exclusion of LVH and coronary artery disease, subclinical cardiomyopathy was identified in 24 of 66 patients. Subclinical disease could not be predicted by BNP.

CONCLUSIONS

Even after exclusion of asymptomatic ischemia and hypertrophy, subclinical systolic and diastolic dysfunction occurs in a significant number of patients with type 2 diabetes. However, screening approaches, including BNP, do not appear to be sufficiently sensitive to identify subclinical dysfunction, which requires sophisticated echocardiographic analysis.

Prognostic role of B-type natriuretic peptide levels in patients with type 2 diabetes mellitus

OBJECTIVES

We hypothesized that B-type natriuretic peptide (BNP) levels can predict cardiac mortality in diabetic patients.

BACKGROUND

Detection of cardiovascular disease in diabetics can be difficult until overt events occur.

METHODS

A total of 482 diabetics (majority male with type 2 diabetes) at the Veterans Affairs Medical Center San Diego were divided into two groups: 1) referred patients for echocardiogram on the basis of clinical suspicion of cardiac dysfunction (referred [R], n = 180); 2) patients randomly selected from the diabetic clinic without any suspicion of cardiac dysfunction (not referred [N-R], n = 302). We examined cardiac events and all-cause mortality in relation to initial BNP levels during the follow-up.

RESULTS

A total of 71 (14.7%) patients died during this period: 52 of 180 (29%) in the R group (30 of 52 [58%] cardiac, 10 of 52 [19%] non-cardiac, 2 of 52 [4%] renal, 10 of 52 [19%] unknown cause) and 19 of 302 (6%) in N-R group (6 of 19 [32%] cardiac). The median BNP level in the R and N-R groups who died of cardiac, non-cardiac, and unknown cause was 537 and 87, 80 and 53, and 343 and 38 pg/ml, respectively. The receiver-operating characteristic (ROC) values for mortality in two groups in relation to BNP revealed the area under the curve to be 0.720 and 0.691, respectively (p < 0.01 in both). Among commonly used prognostic indicators in diabetics, only the ROC for triglycerides was significant. The most accurate cut-point in both the N-R group (87%) and R group (61%) was 120 pg/ml of BNP. Cox regression analysis showed BNP to be the most significant predictor of all-cause mortality in the R group. There was a marked decrease in survival in the patient group with BNP >120 pg/ml.

CONCLUSIONS

B-type natriuretic peptide appears to be a reliable predictor of future cardiac and all-cause mortality in diabetic patients.